JP2002156194A - Inspecting method for heat exchanger, and heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique of inspection of a heat exchanger which enables non-contact inspection of a joined state of the heat exchanger. SOLUTION: In the heat exchanger 1 formed by stacking plates 3, 5 and 7 with fins 9 and 11 or spacers inserted between them and joined to them, the stacked plates 3 and 7 in different layers are provided respectively with temperature sensors 13 and 15 to measure a temperature difference or thermal conductivity between them. The state of a joined portion is inspected on the basis of the measured temperature difference or thermal conductivity. In another way, electrodes are provided in place of the temperature sensors so as to measure any of a potential difference, electrical conductivity and electrical resistance between stacked passages. Based on the measured potential difference or others, the state of the joined portion is inspected. Based on a change in the temperature difference, the potential difference or others between the layers cause by a fault of the joined portion, according to this constitution, the state of the joined portion of the heat exchanger can be inspected in a nondestructive manner without destruction of the heat exchanger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for inspecting a heat exchanger, and more particularly, to a technology for inspecting a heat exchanger formed by stacking a plurality of plates with fins or spacers interposed therebetween.

[0002]

2. Description of the Related Art Heat exchangers formed by laminating fins or spacers between a plurality of plates, such as a heat exchanger called a plate fin type, are used in automobiles,
It is widely used as an indispensable element for cooling gas and the like mainly in the fields of industrial equipment and electronic equipment. Such a heat exchanger is disclosed in JP-A-9-15548.
As described in, for example, Japanese Patent Application Laid-Open No. 7-107, a fin or a spacer made of a copper member, a copper alloy member, an aluminum alloy, or the like, which has been processed and formed in advance, is bonded to a plate.

In general, welding, diffusion bonding, brazing, soldering, and the like are used for joining copper, copper alloys, aluminum alloys, and the like. For example, a heat exchanger is manufactured by a brazing method in which a brazing is previously placed on a brazing portion of a plate material processed into a predetermined shape, and members are joined at the brazing portion to perform a heat treatment. .

[0004]

By the way, in the heat exchanger manufactured by bonding the fins or the spacers to the plate as described above, a bonding defect generated at the time of manufacturing or the like, that is, an initial defect of a bonding portion, is reduced. May occur. If a heat exchanger having such an initial failure at the joint is used, the strength of the heat exchanger will be lower than that of a heat exchanger having no initial failure at the joint, and the reliability of the heat exchanger will be reduced. Performance is reduced. Furthermore, even when there is no initial failure of the joint, even if the heat exchanger repeatedly receives the thermal stress generated between the high-temperature fluid and the low-temperature fluid and the stress due to the pressure load of the fluid, the joint may be damaged. Peeling and the progress of the peeling may lead to breakage of the heat exchanger. In addition, the heat transfer area is reduced due to the separation of the joining portion, which leads to a decrease in the cooling capacity of the heat exchanger. Therefore, it is necessary to inspect defects such as initial failure of the joint of the heat exchanger and peeling of the joint caused by use of the heat exchanger.

However, conventionally, there is no method for inspecting the initial failure of the joint portion of the heat exchanger, and a test piece or a simulated heat exchanger is used to prevent the occurrence of the poor connection due to the use of the heat exchanger. It can only be predicted by a fracture test such as a fatigue test under tensile load conditions. For this reason, there is a demand for a technique capable of non-destructively inspecting the state of the joint portion of the heat exchanger.

An object of the present invention is to non-destructively inspect the state of a joint portion of a heat exchanger.

[0007]

According to the heat exchanger inspection method of the present invention, a heat exchanger formed by laminating fins or spacers between a plurality of plates and joining the laminated plates and fins or spacers is provided. This is a method for inspecting an exchanger, and solves the above-mentioned problem by measuring a temperature difference or thermal conductivity between different stacked layers and inspecting a state of a joint portion based on the measured temperature difference or thermal conductivity.
Further, any one of the potential difference, the electric conductivity, and the electric resistance between the different stacked layers is measured, and the state of the joint portion is inspected based on any of the measured electric potential difference, the electric conductivity, and the electric resistance.

According to such an inspection method, a temperature difference, a thermal conductivity, a potential difference, an electrical conductivity, and an electrical conductivity between respective layers caused by a defective joint portion are provided by attaching a temperature sensor or an electrode to the heat exchanger. Based on any change in resistance, the condition of the junction of the heat exchanger can be inspected non-destructively without destroying the heat exchanger.

Further, the heat exchanger of the present invention is a heat exchanger formed by laminating fins or spacers between a plurality of plates and joining the laminated plates and fins or spacers. The above problem is solved by providing a structure in which temperature sensors are provided in different layers. Further, electrodes are provided in different stacked layers.

With this configuration, the temperature sensor or the electrode is connected to a temperature measuring device, or a power supply, a measuring device for measuring any one of electric potential difference, electric resistance, and electric conductivity, and the like. This is preferable because the state of the joint can be easily inspected nondestructively.

Further, if the terminal is provided with a terminal electrically connected to the temperature sensor or the electrode, a device for measuring a temperature difference or an electric state can be easily connected to the terminal, and the heat exchanger can be joined. This is preferable because the state of the portion can be inspected more easily and nondestructively.

In some cases, a compressor is provided with a heat exchanger at a discharge port of the compressor in order to cool and discharge a fluid that has been overheated by compression. In a compressor equipped with such a heat exchanger, use of a heat exchanger in which a flow path formed by sandwiching fins or spacers between plates, such as a plate fin type, is stacked to reduce the size of the compressor. Is considered. However, when a heat exchanger such as a plate fin type is used for the compressor, the heat exchanger may be fatigued due to pulsation of the pressure of the fluid discharged from the compressor, that is, a defect such as peeling of a joint may occur. There is. Therefore, in order to reduce the size of the compressor using a heat exchanger such as a plate fin type, it is necessary to inspect the condition of the joints of the heat exchanger in a non-destructive manner and to know the time of replacement of the heat exchanger. preferable.

[0013] On the other hand, a compressor provided with the heat exchanger according to any one of the above, wherein at least one flow path of the heat exchanger is connected to a discharge port of the compressed fluid. In addition, since the state of the joint portion of the heat exchanger can be inspected and the replacement time of the heat exchanger can be grasped, a heat exchanger such as a plate fin type can be used as the compressor, and the compressor can be downsized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a heat exchanger inspection technique according to the present invention will be described below with reference to FIGS. FIG.
1 is a perspective view showing a schematic configuration of a heat exchanger to which the present invention is applied. FIG. 2 is an exploded perspective view showing a schematic configuration of the heat exchanger. FIG. 3 is a diagram showing a method of inspecting a heat exchanger to which the present invention is applied. FIG. 4 is a diagram illustrating an example of measurement of thermal conductivity. FIG. 5 is a perspective view, partially broken away, showing a schematic configuration of an example of a compressor provided with a heat exchanger to which the present invention is applied.

The heat exchanger 1 of the present embodiment is a plate-fin type heat exchanger. As shown in FIG. 1, the plates 3, 5, and 7 made of three copper plates, the plate 3 and the plate 5
An air flow path fin 9, which is a corrugated fin made of a copper alloy coated with a brazing material, and a cooling water passage which is provided between the plate 5 and the plate 7 and is a plate fin made of a copper alloy coated with a brazing material. Fins 11 and thermocouples 13 and 15 provided on the outer surfaces of the plates 3 and 7 located outside. An air passage 17 is formed between the plate 3 and the plate 5, and a cooling water passage 19 is formed between the plate 5 and the plate 7. In the heat exchanger 1 of the present embodiment, the air flow path 1
7. The cooling water passage 19 has two flow paths. In other words, the cooling water path 19 has a two-layer structure in which fins are sandwiched between plates.

As shown in FIG. 2, such a heat exchanger 1 is preliminarily brazed to the brazing portions of the plates 3, 5, and 7, that is, the portions in contact with the air flow fins 9 or the cooling water fins 11. Set aside, plate 3 and plate 5
The air flow fins 9 and the cooling water fins 11 are interposed between the plates 5 and 7, respectively, and the plates 3, 5, 7 and the air flow fins 9 and the cooling water fins 11 are connected. It is manufactured by a ladle method in which heat treatment is performed by bonding at the attachment portion.

In the present embodiment, the plates 3, 5, and 7 made of a copper plate and the fins 9 for the air passage and the fins 11 for the cooling water passage formed by pressing a copper alloy into a predetermined shape are subjected to a heat treatment for heat exchange. A brazing material is usually used for brazing copper or copper alloy, such as copper, brass brass, phosphor copper brazing, or silver brazing. In addition, various materials such as an aluminum alloy can be used for components constituting the heat exchanger as long as they have thermal conductivity, and further, the heat exchanger can be configured by combining these various materials. it can.

A method of inspecting the heat exchanger of the present embodiment using the heat exchanger 1 having such a configuration will be described. That is, as shown in FIG. 3, the inspection method of the heat exchanger of the present embodiment includes a thermocouple 13 provided on the plate 3 located outside the heat exchanger 1 and a thermocouple 15 provided on the plate 7. Is electrically connected to the temperature difference measuring device 21 to obtain the thermal conductivity from the temperature difference between the plate 3 and the plate 7.

In an inspection for detecting a joint failure occurring during manufacturing, a test heat exchanger or a test piece for a brazed joint portion made of the same material as the material forming the heat exchanger 1 is prepared in advance, and air is tested. The temperature difference between the thermocouple 13 provided on the plate 3 and the thermocouple 15 provided on the plate 7 is measured as shown in FIG. Then, each thermal conductivity is determined. further,
The condition of the joint by brazing the test heat exchanger or the test piece is inspected by an ultrasonic flaw detector or the like, and the area of the joint is determined. In this way, the relationship between the area of the joint and the thermal conductivity is determined.

In an actual inspection of the heat exchanger 1, in a state where air and cooling water are passed to perform heat exchange, as shown in FIG.
The temperature difference between the thermocouple 15 and the thermocouple 15 is measured to determine the thermal conductivity. By comparing the obtained thermal conductivity with the previously determined relationship between the area of the joint and the thermal conductivity, it is possible to detect an initial failure of the joint due to brazing.

In order to detect the occurrence and progress of defective joints due to the use of the heat exchanger 1, that is, to detect the occurrence and progress of peeling of the joined portions, the state in which the heat exchanger 1 is in use,
That is, as shown in FIG. 4, the temperature difference between the thermocouple 13 provided on the plate 3 and the thermocouple 15 provided on the plate 7 in a state where heat exchange is performed by flowing air and cooling water. Measure and monitor. The occurrence and progress of the peeling of the bonded portion can be detected by a decrease in the value of the temperature difference from an initial value in a substantially stable state.

Further, a fatigue test is performed under tensile load conditions using a test heat exchanger, and the peeling of the brazed joint in the process of the fatigue test is measured with an ultrasonic flaw detector or the like, and the thermal conductivity and the thermal conductivity are measured. Check the relationship. Thereby, the relationship between the peeled area of the brazed joint and the thermal conductivity can be understood. Using this, a decrease in the strength of the heat exchanger can be predicted from the thermal conductivity. Therefore, it is possible to predict the remaining life of the heat exchanger and replace it before destruction.

As described above, according to the inspection method of the heat exchanger of the present embodiment, the change of the temperature difference measured by the thermocouples 13 and 15 provided on the outer plates 3 and 7 and the temperature difference measuring device 21, Or, based on the thermal conductivity obtained from the measured temperature difference, etc., the initial failure of the joint of the heat exchanger, the failure due to the peeling of the joint during the use of the heat exchanger, and the progress thereof, etc. Can be inspected without destruction. That is, the joining state of the heat exchanger can be inspected in a non-contact manner.

Further, since the initial failure generated at the time of manufacturing or the like can be inspected in a non-destructive manner, it is possible to judge the quality by inspecting the quality of the joined portion. In addition, it is possible to sort out defective products at the junction before shipment, so that the reliability of the heat exchanger can be improved. In addition, since the progress of the failure due to the peeling of the joint portion generated during the use of the heat exchanger can be inspected nondestructively, it is possible to specify the time to replace the heat exchanger, which is useful for maintenance.

Further, in the heat exchanger 1 of the present embodiment, the thermocouple 13 provided on the plate 3 and the thermocouple 15 provided on the plate 7 are simply electrically connected to the temperature difference measuring device 21. Can be easily inspected in a non-contact manner.

In this embodiment, the temperature difference is measured,
Although the thermal conductivity is determined from the measured temperature difference, a configuration in which the thermal conductivity is directly measured may be employed. Furthermore, although a thermocouple is used as the temperature sensor, various temperature sensors can be used without being limited to the thermocouple.

In the present embodiment, the thermocouples 13 and 15 are attached to the two outermost plates 3 and 7, respectively. However, three or more channels including such plates and fins are provided. In the case of a configuration in which the temperature sensors are stacked, a temperature sensor such as a thermocouple can be attached to a plate at an intermediate position.

Here, a screw compressor will be described as an example of a compressor provided with the heat exchanger 1 of the present embodiment. As shown in FIG. 5, the screw compressor 23 shown here is provided in a rotor section 25 for compressing air by engagement of the rotor, a motor 27 for driving the rotor to rotate, and a discharge path of the air compressed by the rotor section 25. Heat exchanger 1 and casing 29 for housing heat exchanger 1
It is composed of In the heat exchanger 1, the air flow path 17 of the heat exchanger 1 communicates with the discharge path of the air compressed by the rotor unit 25, and the heat is compressed and superheated through the air flow path 17 of the heat exchanger 1. The cooled air to the cooling water flow path 1 of the heat exchanger 1
9 is cooled by cooling water flowing therethrough.

In a general-purpose air compressor, for example, about 2
The air at 00 ° C. is cooled using water at normal temperature, and the air is compressed to a pressure of, for example, about 1 MPa. Therefore, the heat exchanger 1 provided in such a compressor 23 receives a thermal stress generated between a high-temperature gas and a low-temperature liquid, a stress due to a gas and liquid pressure load, and the like. In particular, in a screw compressor or a reciprocating compressor as shown in this example, the pulsation of the discharged air is larger than that of other compressors, so that the stress due to the pressure load is greater and acts on the heat exchanger. For this reason, when a plate fin type heat exchanger or the like is used as the heat exchanger provided in the compressor, there is a possibility that defects such as peeling of a joint portion may occur due to the influence of these stresses.

By the way, if the plate fin type heat exchanger is used for the compressor, the plate fin type heat exchanger can be downsized as compared with other heat exchangers. it can. However, as described above, in addition to the possibility that defects such as peeling of the joint portion may occur due to the influence of thermal stress or stress due to pressure load, the occurrence and progress of the defect of the joint portion may be reduced by the conventional inspection method. There is no non-destructive inspection method, and it is not possible to predict when to replace the heat exchanger. Therefore, frequent maintenance work of the heat exchanger is required, and it is difficult to use the plate fin type heat exchanger for the compressor.

On the other hand, if the inspection method and the heat exchanger of the present embodiment are used, it is possible to non-destructively inspect the occurrence and progress of the defect at the joint portion of the heat exchanger, and to specify the time for replacing the heat exchanger. Therefore, the plate fin heat exchanger can be used for the compressor, and the compressor can be downsized.

(Second Embodiment) A second embodiment of a liquefied gas supply apparatus according to the present invention will be described with reference to FIGS. FIG. 6 is a perspective view showing a schematic configuration of a heat exchanger to which the present invention is applied. FIG. 7 is a diagram showing a method of inspecting a heat exchanger to which the present invention is applied.
FIG. 8 is a diagram illustrating an example of measurement of a potential difference. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and the configuration and features different from those in the first embodiment will be described.

The difference between the present embodiment and the first embodiment is that the failure of the junction of the heat exchanger is detected as a change in the electrical state. That is, as shown in FIG. 6, the heat exchanger 31 of the present embodiment has five plates 3, 5, 3 a, 5 a, 7, between the plate 3 and the plate 5, and between the plate 3 a and the plate 5 a The air flow fins 9 and 9a, which are corrugated fins provided with brazing material and provided between the plates 5 and 3a,
And cooling water channel fins 1 provided between the plate 5a and the plate 7 and being plate fins coated with brazing material.
1, 11a, the application electrodes 33 and 35 provided on the outer surfaces of the plates 3 and 7 located outside, and the measurement electrodes 37 and 39 provided on the side surfaces of the plates 3a and plate 5a located in the center, etc. It is composed of

An air passage 17 is provided between the plates 3 and 5, a cooling water passage 19 is provided between the plates 5 and 3a, and an air passage 1 is provided between the plates 3a and 5a.
7a, and a cooling water passage 19a is formed between the plate 5a and the plate 7. Further, in the heat exchanger of the present embodiment, the air flow paths 17, 17a, the cooling water paths 19, 19
a), in other words, it has a four-layer structure in which fins are sandwiched between plates.

A method for inspecting the heat exchanger of the present embodiment using the heat exchanger 31 having such a configuration will be described. That is, as shown in FIG. 7, the inspection method of the heat exchanger of the present embodiment includes the application electrode 33 provided on the plate 3 located outside the heat exchanger 31 and the application electrode 35 provided on the plate 7. , A power supply 41 is electrically connected, and a potential difference measuring device 43 is electrically connected to the measurement electrode 37 provided on the plate 3a and the measurement electrode 39 provided on the plate 5a.

As in the first embodiment, a test heat exchanger or a test piece is prepared in order to detect a joint failure occurring during the manufacturing process. As shown in FIG. 7, a constant voltage is applied between the plate 3 and the plate 7 by the application electrode 33 provided on the plate 3 and the application electrode 35 provided on the plate 7, and the plate 3a
The potential difference between the measurement electrode 37 provided on the plate 5a and the measurement electrode 39 provided on the plate 5a is measured, and the relationship between the area of the joint portion and the potential difference is obtained in advance.

In an actual inspection of the heat exchanger 31, the plate 3 and the plate 7 are formed by the applied electrode 33 provided on the plate 3 and the applied electrode 35 provided on the plate 7 in a state where air or cooling water is not allowed to flow. A constant voltage is applied in between, and the potential difference between the measurement electrode 37 provided on the plate 3a and the measurement electrode 39 provided on the plate 5a is measured. By comparing the obtained potential difference with a previously determined relationship between the area of the joint and the potential difference, it is possible to detect an initial failure of the joint due to brazing.

In order to detect the occurrence and progress of defective joints due to the use of the heat exchanger 31, that is, to detect the occurrence and progress of separation of the joined portions, the state in which the heat exchanger 31 is in use, ie, air and cooling In a state where heat exchange is performed by flowing water, as shown in FIG. 8, an applied electrode 33 provided on the plate 3 and an applied electrode 35 provided on the plate 7 maintain a constant distance between the plate 3 and the plate 7. A voltage is applied, and the potential difference between the measurement electrode 37 provided on the plate 3a and the measurement electrode 39 provided on the plate 5a is measured and monitored. The occurrence and progress of the peeling of the bonding portion can be detected by increasing the value of the potential difference from the initial value in a substantially stable state.

Further, a fatigue test is performed under tensile load conditions using a test heat exchanger or the like. Check the relationship. Thereby, the relationship between the peeled area of the brazed joint and the potential difference can be understood. Using this, the strength decrease of the heat exchanger can be predicted from the potential difference. Therefore, it is possible to predict the remaining life of the heat exchanger and replace it before destruction.

In the case where the heat exchanger is inspected based on the electrical state while in use, depending on the electric conductivity of the liquid flowing through the flow path of the heat exchanger and the degree of change in the electric conductivity. In some cases, it is not possible to accurately detect a defect in the joint portion of the heat exchanger. In such a case, a liquid having a known electric conductivity or a liquid having a small change in potential conductivity, such as pure water, is used as a test liquid, and a liquid flowing through a heat exchanger is used for such a test. The inspection may be performed by replacing the liquid.

As described above, according to the method for inspecting a heat exchanger of the present embodiment, it is also possible to inspect the joining state of the heat exchanger in a non-contact manner. Further, in the heat exchanger of the present embodiment, FIG.
In the case of a heat exchanger having a multi-layered structure, a constant voltage is applied to the two outermost plates, and a partial potential difference between the respective layers is measured to cause separation of a joint portion or the like. Defective parts can be specified. In other words, a specific portion can be inspected depending on the position of the measurement electrode.

Further, when a conductive material such as copper or iron is used as the material of the heat exchanger, the method of measuring the temperature difference or the thermal conductivity of the first embodiment is replaced with the method of the present embodiment. It is effective to perform the inspection based on the potential difference. Further, in the present embodiment, the potential difference is measured, but the inspection can be performed by measuring the electric conductivity or the electric resistance instead of measuring the potential difference.

(Third Embodiment) A third embodiment of the liquefied gas supply apparatus to which the present invention is applied will be described with reference to FIGS. FIG. 9 is a partially cutaway perspective view showing a schematic configuration of a heat exchanger to which the present invention is applied. FIG. 10 is a perspective view showing a state where the heat exchanger is inserted into the casing. In the present embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted. The configuration and features different from those in the first and second embodiments will be described. I do.

This embodiment is different from the first embodiment in that, as in the second embodiment, a failure in the junction of the heat exchanger is detected as a change in the electrical state.
This embodiment is different from the second embodiment in that:
The terminal is provided at the end of the wiring portion of the application electrode or the measurement electrode. That is, as shown in FIG. 9, the heat exchanger 45 of the present embodiment has substantially the same configuration as that of the second embodiment, and includes five plates 3, 5, 3a, 5 made of copper plate.
a, 7, between plate 3 and plate 5, and plate 3a
And air passage fins 9 and 9a, which are corrugated fins provided between the plate 5a and the plate, and provided between the plate 5 and the plate 3a and between the plate 5a and the plate 7, respectively, to cover the brazing material. And cooling water channel fins 11 and 11a.

In the heat exchanger 45 of the present embodiment, the measurement electrode 47 is provided at the joint between the plate 3 and the air flow fin 9, and the measurement electrodes 49 and 51 are provided at the plate 5 and the air flow fin 9. The measurement electrode 53 is connected to the plate 3a
The measurement electrode 55 is provided at the junction between the plate 5a and the air flow fin 9a. Each measuring electrode 47, 49, 5
The wiring portions 1, 53 and 55 are wired so as to go out of the heat exchanger 45 from the same side surface of the heat exchanger 45,
Terminals 57, 59, 61, and 6 are provided at the ends of each wiring portion.
3, 65 are provided. The application electrodes 33, 35
Are provided on the outer surfaces of the plates 3 and 7, respectively, as in the second embodiment. However, the wiring portions of the application electrodes 33 and 35 extend outside the heat exchanger 45 from the same side surface of the heat exchanger 45. The terminals 67 and 69 are provided at the ends of the respective wiring portions. Note that FIG. 9 does not show the applied electrode 33 and the terminal 67 of the applied electrode 33 because a part of the plate 3 is broken.

In the heat exchanger 45 according to the present embodiment, when the heat exchanger 45 is inspected by a periodic inspection or the like, a wire from a power supply is connected to the terminals 67 and 69 of the application electrodes 33 and 35, and a potential difference and an electric The wiring of the measuring device such as the resistance and the electric conductivity is connected to the terminals 67 and 69 of the applying electrodes 33 and 35 and the terminals 5 of the measuring electrodes 47, 49, 51, 53 and 55.
7, 59, 61, 63, and 65, wiring from a power supply and wiring of a potential difference measuring instrument can be easily connected. Therefore, the joining state of the heat exchanger can be inspected more easily without contact.

Further, in the heat exchanger 45 of this embodiment,
As shown in FIG. 10, even when the heat exchanger 45 is housed in the casing 71 or the like, the terminals 67 and 69 of the application electrodes 33 and 35, and the measurement electrodes 47, 49, 51, 53, and 5
5 terminals 57, 59, 61, 63, 65 are casing 7
1, the inspection can be performed without removing the heat exchanger from the housing of the device provided with the heat exchanger or the casing that houses the heat exchanger. Therefore, the inspection work of the heat exchanger can be simplified.

In the first, second, and third embodiments, the heat exchanger is formed with the air flow path fins or the cooling water path fins interposed between the plates. Not limited to this, heat exchangers formed by joining these with fins or spacers between plates, such as heat exchangers formed with spacers instead of fins between plates, etc. Applicable. The present invention is not limited to a heat exchanger that performs heat exchange between a gas and a liquid, but is also applicable to a heat exchanger that performs heat exchange between a gas and a gas or between a liquid and a liquid.

[0049]

According to the present invention, the condition of the joint of the heat exchanger can be inspected in a non-contact manner.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a first embodiment of a heat exchanger to which the present invention is applied.

FIG. 2 is an exploded perspective view showing a schematic configuration of a heat exchanger.

FIG. 3 is a diagram showing a first embodiment of a heat exchanger inspection method according to the present invention.

FIG. 4 is a diagram illustrating an example of measurement of a temperature difference.

FIG. 5 is a perspective view, partially broken away, showing a schematic configuration of an example of a compressor including a heat exchanger to which the present invention is applied.

FIG. 6 is a perspective view showing a schematic configuration of a second embodiment of the heat exchanger to which the present invention is applied.

FIG. 7 is a view showing a second embodiment of the heat exchanger inspection method according to the present invention.

FIG. 8 is a diagram illustrating an example of measurement of a potential difference.

FIG. 9 is a perspective view showing a schematic configuration of a third embodiment of the heat exchanger to which the present invention is applied.

FIG. 10 is a perspective view showing a state where the heat exchanger is inserted into a casing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchanger 3, 5, 7 plate 9 Air flow path fin 11 Cooling water path fin 13, 15 Thermocouple 17 Air flow path 19 Cooling water flow path

Claims (6)

[Claims] 1. A method for inspecting a heat exchanger formed by laminating fins or spacers between a plurality of plates and joining the laminated plates and the fins or spacers, the method comprising: A method for inspecting a heat exchanger, wherein a temperature difference or a thermal conductivity of the heat exchanger is measured, and a state of a joint portion is inspected based on the measured temperature difference or the thermal conductivity. 2. A method for inspecting a heat exchanger formed by laminating fins or spacers between a plurality of plates and joining the laminated plates and the fins or spacers, the method comprising: A method for inspecting a heat exchanger, wherein any one of a potential difference, an electric conductivity, and an electric resistance is measured, and a state of a joint portion is inspected based on any of the measured electric potential difference, the electric conductivity, and the electric resistance. 3. A method for inspecting a heat exchanger formed by stacking fins or spacers between a plurality of plates and bonding the stacked plates and the fins or spacers, wherein the different layers are stacked. Heat exchangers each having a temperature sensor. 4. A method for inspecting a heat exchanger formed by stacking fins or spacers between a plurality of plates and joining the stacked plates and the fins or spacers, wherein the stacked different layers A heat exchanger comprising electrodes. 5. The heat exchanger according to claim 3, further comprising a terminal electrically connected to the temperature sensor or the electrode. 6. A compressor comprising the heat exchanger according to claim 3, wherein at least one of the flow passages of the heat exchanger is connected to a discharge port of a compressed fluid. .